Heat-treating furnace



0 heating elements 18 which are illustrate Patented Mar. 10, 1931A UNITED STATES PATENT OFFICE SVEN PAUL AXELL, 0F MANSFIELD, OHIO, ASSIGNOR T0 WESTINGHOUSE ELECTRIC & MANUFACTURING COMPANY, A. CCBPORATION OF YENNSYLVANIA HEAT-TREATING FURNACE Application filed May 21, 1929.` Serial No. 364,717.

M invention relates to furnaces and more particularly to heat ,treating furnaces of the conveyor type.

An object of f ture including a plurality of portions to .permit of obtaining a predetermined and adjustable cooling curve of a heated article.

Another object of my invention is to provide a plural-part furnace structure that shall embody an endless conveyor of substantially fixed extent of travel to move an article to be heat-treated, first through a heated member and then through a non-heat insulated cooling muiile to greatly reduce the teinperature initially and then to obtain any desired temperature curve in a heat-insulated cooling chamber.

1n racticing my invention, l' provide a heate heat-insulating chamber, a non-heatinsulated cooling munie permanently connected to the heated chamber structure at one end thereof and a heat-insulated cooling chamber, telescoping with the cooling inutile, the muiile and the two chambers being longitudinally coaxially aligned, in combination with a horizontal conveyor for moving an article through said chambers and muiiie in predetermined sequence.

In the single sheet of drawings,

Figure 1 is a view, in vertical longitudinal section, through a furnace assembly embodying"my invention, o

ig. 2 is a view, in vertical lateral section, through a heated chamber, taken on the line II-II of Fig. 1, and

Fig. 3 is a view in vertical lateral section, maken on the line iii- Iii of Fig. 1.

A furnace assembly or structure 11 includes a furnace 12, a cooling muie 13, a cooling chamber 14 and an endless conveyor 16. The furnace 12 includes a plurality of side, bottom, top and end walls which may be made of a plurality of bricks or blocks of suitable Ahigh-temperature-resisting and heat-insulatin refractory material to enclose a chamber 1g.

Heating means for the chamber 17 are shown as including top and bottom electricmy invention is to provide a 'zi-relatively simple and effective furnace strucschematicall onl as they may be of any suitable or esire type and may be located either as shown, adjacent to the top and the bottom of the chamber 17 or at the sides thereof, in accordance with the general shape of the articles to be heat treated.

.It is to be understood that suitable provision is made for supporting the heating elements which, in the case of the upper heating elements 18, may include a plurality of lugs 19 fitted into the side walls and supporting the metallic and refractory supporting members of the heating elements. As any suitable or desired type of electric-heating element, or, in fact, an kind of heating means, may be employe I do not deem it necessary to illustrate or describe the construction of the heating elements, the support thereof and the terminal construction in greater detail.

A preheatin muiiie 21 is provided at the entering end o the furnace 12 and comprises a plurality of side, top and bottom walls made of refractory heat-insulating and -hightemperature-resisting materials, usually employed for such pur oses. The chamber of the muile 21 is coaxially and longitudinally aligned with the chamber 17 which, as shown, may be of an suitable length, and, in the articular em odiment shown in the drawings, is of substantially rectangular shape in lateral section.

Supporting means for the furnace 12 and the inutile 21 may comprise metal members 22, which may cooperate with other structural metal members 23, in a manner well known in the art, to cooperate with, and hold the walls of the furnace part 12 in plriper operative positions relatively to, each o er.

The cooling muiile 13 may be of substantially rectangular shape in lateral section and may be made of a single metal casting or, if desired, it may be made of sheet metal shaped to the desired dimensions and form. No heating insulation is used on this cooling muiile, one end of which extends intothe leaving-end wall of the furnace 12 'to be coaxially and longitudinally aligned with the d chamber 17.

The heat-insulated cooling chamber 14, comprises side, top and bottom walls of a suitable heat-insulating refractory material, the Walls being of a predetermined thickness, in accordance with the rate of cooling or the maintenance of a predetermined curve of temperature, as will be hereinafter more clearly set forth.

The walls of the cooling chamber 14 may be constructed and maintained in proper operative positions relatively to each other in any suitable or desired manner, and such metallic framework as may be necessary to hold the parts are to be included in my structure, even though that may not be specifically shown in the drawings. The structure of the cooling chamber is located on a truck 24 having a plurality of sets of wheels 26 which move on a pair of rails 27, thereby permitting adjustable location of the cooling chamber 14 relatively to the cooling muiiie 13.

The outer end of the cooling muille 13 interits with the inner end of the cooling chamber 14 in order that any desired degree of overlap of the cooling mule and of the coolin chamber may be obtained.

gfhe conveyor 16 is illustrated schematically onl and is tobe considered as including or embo ying an endless chain which may move in guide members 28 of substantially channel section, the plurality of trays which may be secured to the endless chain and be moved thereby being supported by tray-guides 29, each of angle-bar shape in lateral section, which are suitably secured to the respective chamber and muilie structures, in a manner well known in the art.

Drums 31 and 32 are provided, one at each end of the furnace structure hereinbefore described,'pedestals 33 and 34 being provided therefor and being ixedly secured to a suitable foundation.

Any desired type of motor means may be provided to cause continuous movement of the endless conveyor and, as any suitable or desired type of such device may be employed, I have not shown it in detail.

The furnace assembly illustrated in the drawings is particularly adapted for the heat treatment of relatively flat objects. These objects may be manually or automatically moved upon the trays of the endless conveyor at the entering end of the furnace 12 and, particularly just outside of the preheating mule 21, and will be moved, at a predetermined speed, through the chamber 17 to be heated to a predetermined temperature therein. It is desired to greatly reduce this temperature immediately after the articles leave the chamber 17 and this is effected in the nonheat-insulated cooling muiile 13 which, as hereinbefore set forth, may be of any suitable length and the wall of which may be of any suitable thickness.

After a relatively large drop in temperature has been effected during the movement of an article through the muiile 13, it is desired either that the articles be maintained at or near this lower temperature or that a predetermined rate of cooling be eili'ected in the 70 cooling chamber 14. In order to be able to maintain the temperaturel of the articles at a predetermined value, or to obtain a predetermined cooling curve thereof, the cooling chamber 14 may be provided with heating 75 elements, indicated schematically at 36 and 37 and indicated also as being supported from and near the roof of the cooling chamber. A plurality of electric-heating elements may be provided to be energized from a suitable source of supply of electric energy and controlled by means (not shown) in order to obtain a predetermined curve of temperature of the articles.

It is obvious that, if the non-heat-insulated cooling muiile 13 be made relatively long, and if the wall thereof be made relatively thin, a relatively large drop of temperature of the articles being moved therethrough will be obtained. If it is desired to decrease this reduction in temperature, it can be done by moving the cooling chamber 14 and the trucl; structure 24 closer to the heated furnace 12 the muilie 13 interfitting and telescoping 9 with the cooling chamber 14.

The device embodying my invention thus provides a composite or plural-part furnace structure embodying an endless conveyor of substantially fixed extent of travel and longitudinally aligned muiile and chamber parts,

one of which is longitudinally adjustable relatively to the other to permit of obtaining any predetermined cooling curve in accordance with the work to be done in the heat treating furnace.

Various modifications may be made in the device embodying my invention without de;l parting from the spirit and scope thereof and I desire, therefore, that only such limitations shall be placed thereon as are imposed by the aligned with the heated chamber and embodying a heat-insulated cooling chamber adjustably spaced from the heated chamber and a non-heat-insulated cooling mule located between the two chambers.

3. In a heat treating furnace having a heated chamber and a conveyor for moving articles to be heat treate therethrough, means for obtaining a. predetermined and adjustable rate of cooling of articles heated in said chamber, said means including a cooling chamber comprising two vparts having relatively longitudinal adjustability coaxially aligned with the heated chamber and with eachother, one of said parts telescoping within the other.

4. In a heat treating furnace having a i heated chamber and a conveyor for moving articles to be heat treated therethrough, means for obtaining a predetermined and adjustablerate of cooling of articles heated in heated art1cle initially and then maintainingy the article at a predetermined curve of temperature for a] predetermined time, said means including a nonfheat-insulated coolin muiile permanently connected to the heate chamber at one end thereof, a cooling chamber aligned longitudinally with the muie and the' heated chamber and telescoping with the cooling mule, the conveyor traversin the heated chamber, the cooling mulle an the cooling chamber in sequence and means for varyin the amount of overlap of the cooling mu e and the cooling chamber.

In testimony whereof, I have hereunto subscribed my name this 9 da of May, 1929.

' SVEN AUL AXELL. 

